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what do these shapes all have in common
they're all two-dimensional shapes with
four sides and four angles
these are known as quadrilaterals
quad means four laterals mean sides
in this video we're going to look at the
properties of quadrilaterals in more
detail
so they all have four sides they all
have four angles
they all have four vertices or corners
what about the sum of the interior
angles
the interior angles always add up to 360
degrees
we're going to have a look at these six
quadrilaterals in more detail
before we start did you know that
squares rectangles and rhombuses are all
types of parallelograms
so let's start at the top with the one
you probably already know all about
squares
four equal sides four right angles
and opposite sides are parallel
what about rectangles
also four right angles and opposite
sides are parallel
but
this time the lengths aren't all the
same
opposite sides are equal in length
these
and these
did you know that a square is a type of
rectangle
what about a rhombus
what do you notice about its sides and
angles pause the video and have a think
four equal sides
opposite sides are parallel and equal in
length
opposite angles are equal
i always think of a rhombus as a tipped
over square
did you know that a square is a type of
rhombus so now parallelograms
just like a rhombus is a tipped over
square a parallelogram is a tipped over
rectangle
i told you earlier that squares
rectangles and rhombuses are all types
of parallelograms
so what does it mean to be a
parallelogram
pause the video and have a think
they have parallel opposite sides
that are equal in length so these and
these
the opposite angles are also equal like
in rhombuses
squares rectangles and rhombuses all
meet these requirements hence they're
parallelograms
in england we call them trapeziums in
america they're trapezoids
they simply have one pair of parallel
sides
as trapeziums have such a simple
definition
it actually means
that squares
rectangles rhombuses parallelograms are
also all trapeziums
last up we have kites
what do you notice about our final type
of quadrilaterals
pause the video and have a think
they have
two pairs of sides that are equal in
length
they always have one pair of equal
angles
and they're not so important but worth
mentioning the diagonals cross at 90
degrees
so quadrilaterals are actually all very
interconnected by definition a square is
a quadrilateral a trapezium a
parallelogram a rectangle and a rhombus
time to test your knowledge pause the
video answer these questions and click
play when you're ready
how did you get on
so that's the end of quadrilaterals just
remember that they're all very
interconnected and so have similar
properties
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until next time